Liquid fuel composition and method for enhancing combustion efficiency of a liquid fuel

ABSTRACT

A liquid fuel composition includes: a liquid fuel; and a sublimatable organic compound that has a sublimation point lower than 45° C. at atmospheric pressure, and that includes a skeleton selected from bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese application No. 099138652, filed on Nov. 10, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a liquid fuel composition and a method for enhancing combustion efficiency of a liquid fuel using a sublimatable organic compound.

2. Description of the Related Art

As the global energy crisis and environmental pollution become more serious, scientists are devoting efforts to investigate alternative energy resources as well as develop methods for enhancing the combustion efficiency and reducing the usage of present energy sources such as fossil fuels. For the latter purpose, aside from modifying the mechanical structure of combustion equipment, use of fuel additives to improve combustion efficiency is also widely employed. For example, methyl tertiarybutyl ether (MEBT) has been added in unleaded gasoline in an amount of about 4-10 wt % to achieve complete combustion of gasoline. However, exposure to MEBT for a long time is likely to cause tissue/organ damage or cancer. Camphor and naphthalene are also used as fuel additives. U.S. Pat. No.5,266,082 discloses a fuel additive for improving combustion of a hydrocarbon fuel and substantially reducing motor vehicle exhaust emissions. The fuel additive includes at least 90 wt % of a carrier liquid, a bicyclic aromatic component such as naphthalene, zinc oxide, and metal oxides. However, since camphor and naphthalene have relatively high melting points, i.e., 176-180° C. and 179.75° C., respective, they posses poor burning characteristics, thereby resulting in heavy smoke and carbon deposits.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a liquid fuel composition and a method using the same that may overcome the above drawbacks associated with the prior art.

According to a first aspect of the present invention, a liquid fuel composition includes: a liquid fuel; and a sublimatable organic compound that has a sublimation point lower than 45° C. at atmospheric pressure, and that includes a skeleton selected from the group consisting of bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.

According to a second aspect of the present invention, a method for enhancing combustion efficiency of a liquid fuel includes: adding a sublimatable organic compound in a liquid fuel, wherein the sublimatable organic compound has a sublimation point lower than 45° C. at atmospheric pressure and includes a skeleton selected from the group consisting of bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the preferred embodiments of the present invention, a liquid fuel composition comprises: a liquid fuel; and a sublimatable organic compound that has a sublimation point lower than 45° C. at atmospheric pressure, and that includes a skeleton selected from the group consisting of bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.

Preferred examples for the sublimatable organic compound are described below according to the skeleton thereof. It should be noted that the sublimatable organic compound is not limited to the following examples. The sublimatable organic compounds containing different skeletons can be simultaneously used in the liquid fuel composition of this invention.

1. Bicycloheptane Skeleton:

Natural compounds include, e.g., borneol, camphene, etc.

Synthesis compounds include, e.g., 2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]-2-heptane having the following formula (1),

4,7,7-trimethylbicyclo[2.2.1]heptanone having the following formula (2),

4,7,7-trimethylbicyclo[2.2.1]heptanone having the following formula (3), etc. Schemes for synthesis of formulas (1), (2), and (3) are shown below.

Scheme for Synthesis of Formula (1)

Scheme for Synthesis of Formula (2)

Scheme for Synthesis of Formula (3)

2. Indane Skeletone:

Natural compounds include, e.g., 5-acetyl-1,1,2,3,3,6-hexamethylindane(phantolide), 4-acetyl-6-tert-butyl-1,1-dimethylindane (celestolide),

1,1,4,4-tetramethyl-6-ethyl-7-acetyl-1,2,3,4-tetra hydronaphthalene(versalide), etc.

3. Pyrone Skeletone:

Natural compounds include, e.g., maltol (3-hydroxy-2-methyl-4-pyrone), etc.

4. Cyclopropane Skeletone:

Synthesis compounds include, e.g.,

2-isobutyl-3-isopropylcyclopropanol having the following formula (4),

2-isobutyl-3-isopropylcyclopropanone having the following formula (5), etc.

5. Cyclobutane Skeletone:

Synthesis compounds include, e.g.,

2-isobutyl-4-ethylcyclobutanol having the following formula(6),2-isobutyl-4-ethylcyclobutanone having the following formula (7), etc.

6. Cyclopentane Skeletone:

Synthesis compounds include, e.g.,

2-isobutyl-4-methylcyclopentanol having the following formula (8),

2-isobutyl-4-methylcyclopentanone having the following formula (9), etc.

7. Cyclohexane Skeletone:

Natural compounds include, e.g., menthol, tert-butylcyclohexanol, etc.

Synthesis compounds include, e.g.,

2-isopropyl-2,5-dihydroxy-5-methylcyclohexanone derived from menthol and having the following formula (10),

1-methyl -1-hydroxy-4-(1-methyl-1-hydroxyethyl)cyclohexane derived from limonene and having the following formula (11),

2-methyl-3,5-dihydroxy-5-(1-methylvinyl)-2-cyclo hexanone derived from carvone and having the following formula (12),

3-methyl-3-hydroxy-6-isopropylcyclohexanone derived from piperitone and having the following formula (13),

5-hydroxy-5-methyl-2-(1-methylethylidene)cyclo hexane derived from pulegone and having the following formula (14),

2-(4-hydroxy-4-methyl-1-cyclohexyl)isopropanol derived from terpineol and having the following formula (15),

1-hydroxy-1-methyl-4-(1-methylethylidene)cyclo hexane derived from terpinolene and having the following formula (16),

1-hydroxy-2-isobutylcyclohexane having the following formula (17),

1-hydroxy-1-isobutylcyclohexane having the following formula (18),

1, 4-dihydroxy-3,6-diisobutylcyclohexane having the following formula (19),

1-hydroxy-3,6-diisobutylcyclohexane having the following formula (20),

1-hydroxy-4-isobutylcyclohexane having the following formula (21), 2-isobutylcyclohexanone having the following formula (22),

1-hydroxl-3-isopropyl-6-methylcyclohexane having the following formula (23), 2-isobutylcyclohexanol having the following formula (24), etc. Schemes for synthesis of formulas (10) to (23) are shown below.

Scheme for Synthesis of Formula (10)

Scheme for Synthesis of Formula (11)

Scheme for Synthesis of Formula (12)

Scheme for Synthesis of Formula (13)

Scheme for Synthesis of Formula (14)

Scheme for Synthesis of Formula (15)

Scheme for Synthesis of Formula (16)

Scheme for Synthesis of Formula (17)

Scheme for Synthesis of Formula (18)

Scheme for Synthesis of Formula (19)

Scheme for Synthesis of Formula (20)

Scheme for Synthesis of Formula (21)

Scheme for Synthesis of Formula (22)

Scheme for Synthesis of Formula (23)

8. Cycloheptane Skeletone:

Synthesis compounds include, e.g.,

4-isopropylcycloheptanol having the following formula (25), 4-isopropylcycloheptanone having the following formula (26), etc.

9. Cyclooctane Skeletone:

Synthesis compounds include, e.g.,

3,7-dimethylcyclooctanol having the following formula (27), 3,7-dimethylcyclooctanone having the following formula (28), etc.

10. Benzene Skeletone:

Synthesis compounds include

1-methyl-2,5-diisobutyl-4-cumene having the following formula (29), etc.

Each of the above sublimatable organic compounds is either a natural compound or a synthetic compound. They are substantially environmental friendly and have little or no impact to the environment.

Preferably, in the liquid fuel composition, the sublimatable organic compound is present in an amount of 0.1-500 grams based on 10 L of the liquid fuel.

Preferably, the liquid fuel of the liquid fuel composition is selected from the group consisting of gasoline, diesel, alcohol, biomass fuel, organic hydrogenated fuel oil, and combinations thereof. Examples of the organic hydrogenated fuel oil include, but are not limited to, cyclohexane, methylcyclohexane, and decahydronaphthalene.

The method for enhancing combustion efficiency of a liquid fuel according to the present invention includes adding the aforesaid sublimatable organic compound(s) in the liquid fuel.

EXAMPLE Examples 1 to 7 (E1-E7)

2.5 grams of a sublimatable organic compound of the present invention was added in a liquid fuel having a predetermined volume so as to form a liquid fuel composition of the present invention. The liquid fuel composition of the present invention was filled in the fuel tank of a vehicle which was subsequently tested to run on a general road in Shenzhen, China with a varying speed. The species of the sublimatable organic compound, the liquid fuel, the amounts of the liquid fuel, the tested vehicle, and the total volume displaced by a cylinder/cylinders of the engine through one revolution, horsepower, and manufacture year of the vehicle for each of Examples 1 to 7 are shown in Table 1. The running mileage of each of Examples 1 to 7 was recorded and is shown in Table 2.

TABLE 1 Amount Horse- of Total volume power Manufacture Sublimatable Organic Liquid Liquid Example Vehicle (c.c.) (hp) Year Compound Fuel Fuel (L) 1 TUCSOND- 2000 136 November 2007 1-hydroxy-4- diesel 50 DX2 isobutylcyclohexane 2 Audi A80 2000 175 October 2002 2-isobutyl- 95RON 60 cyclohexanone unleaded gasoline 3 Honda 3000 200 June 2003 1-hydroxl-3-isopropyl- 97RON 50 Accord 6-methylcyclohexane unleaded gasoline 4 Audi A80 2000 175 October 2002 2-isobutylcyclohexanol 95RON 60 unleaded gasoline 5 Honda 3000 200 June 2003 2-isobutylcyclohexanone 97RON 50 Accord unleaded gasoline 6 Honda 3000 200 June 2003 4,7,7-trimethylbicyclo- 97RON 50 Accord [2.2.1]heptanol unleaded gasoline 7 TUCSOND- 2000 136 November 2007 4,7,7-trimethylbicyclo- diesel 50 DX2 [2.2.1]heptanone

Comparative Examples 1 to 7 (CE1-CE7)

The composition and test conditions of each of Comparative Examples 1 to 7 were the same as those of each of Examples 1 to 7, respectively, except that the liquid fuels used in Comparative Examples 1 to 7 contain no sublimatable organic compounds. The running mileage of each of Comparative Examples 1 to 7 was recorded and is shown in Table 2.

TABLE 2 Example/Comparative Example Mileage E1 560 CE1 480 E2 430 CE2 350 E3 450 CE3 350 E4 460 CE4 350 E5 440 CE5 350 E6 470 CE6 350 E7 590 CE7 480

The results shown in Table 2 indicate that addition of the sublimatable organic compounds of this invention to the liquid fuel can raise the running mileage of the vehicles.

When the sublimatable organic compound of this invention is sublimated in the liquid fuel, the volume of the sublimatable organic compound is increased, thereby resulting in a disturbing flow and a diffusion of Brown Movement in the liquid fuel to allow the liquid fuel to be uniformly heated and thus converted to small molecules or gas state. The sublimated organic compound also assists the diffusion/movement and complete combustion of the liquid fuel with small molecules or gas state. Therefore, with the addition of the sublimatable organic compound in the liquid fuel, the combustion efficiency of the liquid fuel composition of this invention,can be enhanced.

While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements. 

1. A liquid fuel composition, comprising: a liquid fuel, and a sublimatable organic compound that has a sublimation point lower than 45° C. at atmospheric pressure, and that includes a skeleton selected from the group consisting of bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.
 2. The liquid fuel composition of claim 1, wherein said sublimatable organic compound is selected from the group consisting of menthol, borneol, camphene, tert-butylcyclohexanol, maltol (3-hydroxy-2-methyl-4-pyrone), 5-acetyl-1,1,2,3,3,6-hexamethylindane (phantolide), 4-acetyl-6-tert-butyl-1,1-dimethylindane (celestolide), 1,1,4,4-tetramethyl-6-ethyl-7-acetyl-1,2,3,4-tetrahy dronaphthalene(versalide), 2-isopropyl-2,5-dihydroxy-5-methylcyclohexanone, 1-methyl-1-hydroxy-4-(1-methyl-1-hydroxyethyl)cycloh exane, 2-methyl-3,5-dihydroxy-5-(1-methylvinyl)-2-cyclohexa none, 3-methyl-3-hydroxy-6-isopropylcyclohexanone, 5⁻hydroxy-5-methyl-2-(1-methylethylidene)cyclohexane, 2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]-2-heptane, 2-(4-hydroxy-4-methyl-1-cyclohexyl)isopropanol, 1-hydroxy-1-methyl-4-(1-methylethylidene)cyclohexane, 1-methyl-2,5-diisobutyl-4-cumene, 1-hydroxy-2-isobutylcyclohexane, 1-hydroxy-1-isobutylcyclohexane, 1,4-dihydroxy-3,6-diisobutylcyclohexane, 1-hydroxy-3,6-diisobutylcyclohexane, 1-hydroxy-4-isobutylcyclohexane, 4,7,7-trimethylbicyclo[2.2.1]heptanone, 4,7,7-trimethylbicyclo[2.2.1]heptanol, 1-hydroxl-3-isopropyl-6-methylcyclohexane, 2-isobutyl-3-isopropylcyclopropanone, 2-isobutyl-3-isopropylcyclopropanol, 2-isobutyl-4-ethylcyclobutanone, 2-isobutyl-4-ethylcyclobutanol, 2-isobutyl-4-methylcyclopentanone, 2-isobutyl-4-methylcyclopentanol, 2-isobutylcyclohexanone, 2-isobutylcyclohexanol, 4-isopropylcycloheptanone, 4-isopropylcycloheptanol, 3,7-dimethylcyclooctanone, 3,7-dimethylcyclooctanol, and combinations thereof.
 3. The liquid fuel composition of claim 1, wherein said sublimatable organic compound is present in an amount of 0.1-500 grams based on 10 L of said liquid fuel.
 4. The liquid fuel composition of claim 1, wherein said liquid fuel is selected from the group consisting of gasoline, diesel, alcohol, biomass fuel, organic hydrogenated fuel oil, and combinations thereof.
 5. A method for enhancing combustion efficiency of a liquid fuel, comprising: adding a sublimatable organic compound in a liquid fuel, wherein the sublimatable organic compound has a sublimation point lower than 45° C. at atmospheric pressure and includes a skeleton selected from the group consisting of bicycloheptane, indane, pyrone, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and benzene.
 6. The method of claim 5, wherein the sublimatable organic compound is selected from the group consisting of menthol, borneol, camphene, tert-butylcyclohexanol, maltol(3-hydroxy-2-methyl-4-pyrone), 5-acetyl-1,1,2,3,3,6-hexamethylindane(phantolide), 4-acetyl-6-tert-butyl-1,1-dimethylindane(celestolide), 1,1,4,4-tetramethyl-6-ethyl-7-acetyl-1,2,3,4-tetrahy dronaphthalene(versalide), 2-isopropyl-2,5-dihydroxy-5-methylcyclohexanone, 1-methyl-1-hydroxy-4-(1-methyl-1-hydroxyethyl)cycloh exane, 2-methyl-3,5-dihydroxy-5-(1-methylvinyl)-2-cyclohexa none, 3-methyl-3-hydroxy-6-isopropylcyclohexanone, 5-hydroxy-5-methyl-2-(1-methylethylidene)cyclohexane, 2-hydroxy⁻2,6,6-trimethylbicyclo[3.1.1]-2-heptane, 2-(4-hydroxy-4-methyl-1-cyclohexyl)isopropanol, 1-hydroxy-1-methyl-4-(1-methylethylidene)cyclohexane, 1-methyl-2,5-diisobutyl-4-cumene, 1-hydroxy-2-isobutylcyclohexane, 1-hydroxy-1-isobutylcyclohexane, 1,4-dihydroxy-3,6-diisobutylcyclohexane, 1-hydroxy-3,6-diisobutylcyclohexane, 1-hydroxy-4-isobutylcyclohexane, 4,7,7-trimethylbicyclo[2.2.1]heptanone, 4,7,7-trimethylbicyclo[2.2.1]heptanol, 1-hydroxl-3-isopropyl-6-methylcyclohexane, 2-isobutyl-3-isopropylcyclopropanone, 2-isobutyl-3-isopropylcyclopropanol, 2-isobutyl-4-ethylcyclobutanone, 2-isobutyl-4-ethylcyclobutanol, 2-isobutyl-4-methylcyclopentanone, 2-isobutyl-4-methylcyclopentanol, 2-isobutylcyclohexanone, 2-isobutylcyclohexanol, 4-isopropylcycloheptanone, 4-isopropylcycloheptanol, 3,7-dimethylcyclooctanone, 3,7-dimethylcyclooctanol, and combinations thereof.
 7. The method of claim 5, wherein the sublimatable organic compound is present in an amount of 0.1-500 grams based on 10 L of the liquid fuel.
 8. The method of claim 5, wherein the liquid fuel is selected from the group consisting of gasoline, diesel, alcohol, biomass fuel, organic hydrogenated fuel oil, and combinations thereof. 